package cn.tedu.coolshark.filter;

import cn.tedu.coolshark.pojo.vo.UserVo;

import javax.servlet.*;
import javax.servlet.annotation.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
//在urlPatterns里面配置经过过滤器的路径
@WebFilter(filterName = "MyFilter",urlPatterns = {"/admin.html","/insertBanner.html"})
public class MyFilter implements Filter {
    public void init(FilterConfig config) throws ServletException {
    }

    public void destroy() {
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
        //因为要用到子类型里面的属性或方法 所以进行类型强转
        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse res = (HttpServletResponse) response;
        //得到Session对象
        HttpSession session = req.getSession();
        //从Session里面获取登录成功时保存的用户对象
        UserVo user = (UserVo) session.getAttribute("user");
        if (user == null){//未登录
            res.sendRedirect("/login.html"); //让客户端重定向到登录页面
        }else{ //登录过
            chain.doFilter(request,response);
        }
        chain.doFilter(request, response);//放行 允许访问资源
    }
}
